diff options
Diffstat (limited to 'vendor/tiff/src/encoder/compression/deflate.rs')
-rw-r--r-- | vendor/tiff/src/encoder/compression/deflate.rs | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/vendor/tiff/src/encoder/compression/deflate.rs b/vendor/tiff/src/encoder/compression/deflate.rs new file mode 100644 index 0000000..5e7a261 --- /dev/null +++ b/vendor/tiff/src/encoder/compression/deflate.rs @@ -0,0 +1,83 @@ +use crate::{encoder::compression::*, tags::CompressionMethod}; +use flate2::{write::ZlibEncoder, Compression as FlateCompression}; +use std::io::Write; + +/// The Deflate algorithm used to compress image data in TIFF files. +#[derive(Debug, Clone, Copy)] +pub struct Deflate { + level: FlateCompression, +} + +/// The level of compression used by the Deflate algorithm. +/// It allows trading compression ratio for compression speed. +#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)] +#[non_exhaustive] +pub enum DeflateLevel { + /// The fastest possible compression mode. + Fast = 1, + /// The conserative choice between speed and ratio. + Balanced = 6, + /// The best compression available with Deflate. + Best = 9, +} + +impl Default for DeflateLevel { + fn default() -> Self { + DeflateLevel::Balanced + } +} + +impl Deflate { + /// Create a new deflate compressor with a specific level of compression. + pub fn with_level(level: DeflateLevel) -> Self { + Self { + level: FlateCompression::new(level as u32), + } + } +} + +impl Default for Deflate { + fn default() -> Self { + Self::with_level(DeflateLevel::default()) + } +} + +impl Compression for Deflate { + const COMPRESSION_METHOD: CompressionMethod = CompressionMethod::Deflate; + + fn get_algorithm(&self) -> Compressor { + Compressor::Deflate(self.clone()) + } +} + +impl CompressionAlgorithm for Deflate { + fn write_to<W: Write>(&mut self, writer: &mut W, bytes: &[u8]) -> Result<u64, io::Error> { + let mut encoder = ZlibEncoder::new(writer, self.level); + encoder.write_all(bytes)?; + encoder.try_finish()?; + Ok(encoder.total_out()) + } +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::encoder::compression::tests::TEST_DATA; + use std::io::Cursor; + + #[test] + fn test_deflate() { + const EXPECTED_COMPRESSED_DATA: [u8; 64] = [ + 0x78, 0x9C, 0x15, 0xC7, 0xD1, 0x0D, 0x80, 0x20, 0x0C, 0x04, 0xD0, 0x55, 0x6E, 0x02, + 0xA7, 0x71, 0x81, 0xA6, 0x41, 0xDA, 0x28, 0xD4, 0xF4, 0xD0, 0xF9, 0x81, 0xE4, 0xFD, + 0xBC, 0xD3, 0x9C, 0x58, 0x04, 0x1C, 0xE9, 0xBD, 0xE2, 0x8A, 0x84, 0x5A, 0xD1, 0x7B, + 0xE7, 0x97, 0xF4, 0xF8, 0x08, 0x8D, 0xF6, 0x66, 0x21, 0x3D, 0x3A, 0xE4, 0xA9, 0x91, + 0x3E, 0xAC, 0xF1, 0x98, 0xB9, 0x70, 0x17, 0x13, + ]; + + let mut compressed_data = Vec::<u8>::new(); + let mut writer = Cursor::new(&mut compressed_data); + Deflate::default().write_to(&mut writer, TEST_DATA).unwrap(); + assert_eq!(EXPECTED_COMPRESSED_DATA, compressed_data.as_slice()); + } +} |